Capacitor and a dram device including the same

Abstract

A capacitor may include a lower electrode, a dielectric layer structure on the lower electrode, and an upper electrode on the dielectric layer structure. The dielectric layer structure may include a plurality of dielectric layers and at least one insert layer structure between ones of the plurality of dielectric layers. The insert layer structure may include a plurality of zirconium oxide layers and at least one insert layer. The insert layer may be between ones of the plurality of zirconium oxide layers. The capacitor may have a high capacitance and low leakage currents.

What is claimed is: 
     
         1 . A capacitor, comprising:
 an upper electrode including titanium nitride;   a lower electrode facing the upper electrode, the lower electrode being spaced apart from the upper electrode, and the lower electrode including at least one of TiN, Ti, and Nb; and   a dielectric layer structure between the upper electrode and the lower electrode,   wherein the dielectric layer structure includes at least three zirconium oxide layers arranged adjacent to each other and spaced apart from each other, and aluminum oxide layers, each of the aluminum oxide layers interposed between the at least three zirconium oxide layers adjacent to each other, wherein the at least three zirconium oxide layers comprise at least a first zirconium oxide layer, a second zirconium oxide layer, and a third zirconium oxide layer, and the aluminum oxide layers comprise at least a first aluminum oxide layer and second aluminum oxide layer, and   an upper surface and a lower surface of each of the aluminum oxide layers contact the zirconium oxide layers,   wherein the dielectric layer structure comprises,   a first structure facing a bottom of the upper electrode, and including the first aluminum oxide layer, the first zirconium oxide layer, and a first hafnium oxide layer;   a second structure facing a bottom of the first structure, and including the second zirconium oxide layer and the second aluminum oxide layer; and   a third structure disposed under the second structure, facing the upper surface of the lower electrode, and including a second hafnium oxide layer and the third zirconium oxide layer, wherein the second hafnium oxide layer included in the third structure directly contacts the upper surface of the lower electrode.   
     
     
         2 . The capacitor of  claim 1 , wherein, in the first structure, the first hafnium oxide layer, the first zirconium oxide layer, and the first aluminum oxide layer are sequentially stacked in a direction from the upper electrode to the lower electrode. 
     
     
         3 . The capacitor of  claim 1 , wherein the second zirconium oxide layer and the second aluminum oxide layer included in the second structure are sequentially stacked in a direction from the upper electrode to the lower electrode. 
     
     
         4 . The capacitor of  claim 1 , wherein an upper surface of the second structure directly contacts a bottom surface of the first structure. 
     
     
         5 . The capacitor of  claim 1 , wherein the lower electrode includes a stacked structure of titanium nitride and niobium. 
     
     
         6 . The capacitor of  claim 1 , wherein the lower electrode has a pillar shape. 
     
     
         7 . The capacitor of  claim 1 , wherein the dielectric layer structure covers a sidewall and an upper surface of the lower electrode. 
     
     
         8 . A capacitor, comprising:
 a first electrode;   a dielectric layer structure on the first electrode; and   a second electrode including titanium nitride on a dielectric layer structure,   wherein the dielectric layer structure comprises,   at least two aluminum oxide layers spaced apart from each other;   a plurality of hafnium oxide layers spaced apart from each other; and   at least three zirconium oxide layers spaced apart from each other, and
 wherein each of the aluminum oxide layers are interposed between each of the at least three zirconium oxide layers adjacent to each other, and 
   an upper surface and a lower surface of each of the aluminum oxide layers contacts the zirconium oxide layers,
 wherein the number of the zirconium oxide layers included in the dielectric layer structure is greater than the number of the aluminum oxide layers included in the dielectric layer structure, and is greater than the number of the hafnium oxide layers included in the dielectric layer structure. 
   
     
     
         9 . The capacitor of  claim 8 , wherein the at least two aluminum oxide layers comprises a first aluminum oxide layer and a second aluminum oxide layer, the at least three zirconium oxide layers comprises a first zirconium oxide layer, a second zirconium oxide layer, and a third zirconium oxide layer, the plurality of hafnium oxide layers comprises a first hafnium oxide layer and a second hafnium oxide layer, and the dielectric layer structure includes a first structure facing the bottom of the second electrode, and the first structure includes the first aluminum oxide layer, the first zirconium oxide layer, and the first hafnium oxide layer stacked. 
     
     
         10 . The capacitor of  claim 9 , wherein the dielectric layer structure includes a second structure facing the bottom of the first structure, and the second structure includes the second zirconium oxide layer and the second aluminum oxide layer stacked. 
     
     
         11 . The capacitor of  claim 10 , wherein the dielectric layer structure includes a third structure including at least one of the second hafnium oxide layer and the third zirconium oxide layer, and the third structure is disposed below the second structure and faces an upper surface of the first electrode. 
     
     
         12 . The capacitor of  claim 11 , wherein the third structure includes the second hafnium oxide layer and the third zirconium oxide layer. 
     
     
         13 . The capacitor of  claim 8 , wherein the first electrode includes titanium nitride and niobium stacked. 
     
     
         14 . The capacitor of  claim 8 , wherein the first electrode has a pillar shape. 
     
     
         15 . The capacitor of  claim 8 , wherein a thickness of each of the aluminum oxide layers included in the dielectric layer structure is less than a thickness of each of the hafnium oxide layers included in the dielectric layer structure. 
     
     
         16 . The capacitor of  claim 8 , wherein a thickness of each of the aluminum oxide layers included in the dielectric layer structure is less than a thickness of each of the zirconium oxide layers included in the dielectric layer structure. 
     
     
         17 . The capacitor of  claim 8 , further comprising an upper interface layer that contacts a lower surface of the second electrode. 
     
     
         18 . A capacitor, comprising:
 an upper electrode including titanium nitride;   a lower electrode facing the upper electrode, the lower electrode being spaced apart from the upper electrode, and the lower electrode including at least one of TiN, Ti, and Nb; and   a dielectric layer structure between the upper electrode and the lower electrode,   wherein the dielectric layer structure comprises,   a first structure facing a bottom of the upper electrode, and the first structure including a first hafnium layer, a first zirconium oxide layer, and a first aluminum oxide layer sequentially stacked in a direction from the upper electrode to the lower electrode;   a second structure contacting a bottom of the first structure, and the second structure including a second zirconium oxide layer and a second aluminum oxide layer sequentially stacked in the direction from the upper electrode to the lower electrode;   a third structure disposed under the second structure, the third structure including a third zirconium oxide layer and a second hafnium oxide layer; and   an upper interface layer interposed between the upper electrode and the first structure,   wherein an upper surface of the first aluminum oxide layer contacts the first zirconium oxide layer, and a lower surface of the first aluminum oxide layer contacts the second zirconium oxide layer, and   wherein an upper surface of the second aluminum oxide layer contacts the second zirconium oxide layer, and a lower surface of the second aluminum oxide layer contacts the third zirconium oxide layer.   
     
     
         19 . The capacitor of  claim 18 , wherein the upper interface layer includes Al 2 O 3 , MgO, BeO, Y 2 O 3 , La 2 O 3 , CaO, or SiO 2 .